refactor(skills): streamline generic skill contracts

[Alan-TheGentleman]

Context

This is PR 2 of a chained feature-branch refactor to standardize repository skills around a clearer runtime format.

This batch applies the same base contract to the generic skills so they are shorter, more operational, and easier for agents to execute consistently.

Description

• Refactors the generic foundation skills used across Prowler implementation work
• Converts tdd, react-19, typescript, tailwind-4, vitest, and pytest into compact runtime contracts
• Standardizes decision gates, output contracts, and local-only references across the batch

Chain Context

• Strategy: feature-branch-chain
• Tracker branch: feat/skill-style-guide-refactor
• Depends on: refactor(skills): align meta skills with style guide #11087
• Current PR: 2 / 4 📍
• Base branch: refactor/skill-style-meta-foundation
• Next planned PR: refactor/skill-style-core-prowler

feat/skill-style-guide-refactor
└── refactor/skill-style-meta-foundation
    └── refactor/skill-style-core-generic 📍
        └── refactor/skill-style-core-prowler
            └── refactor/skill-style-specialists

Out of scope for this PR:

• Prowler workflow skills such as prowler, prowler-api, prowler-ui, jsonapi, and django-drf
• Oversized specialist skills such as prowler-compliance, django-migration-psql, postgresql-indexing, and prowler-attack-paths-query

Steps to review

1. Review the six updated generic skills:
   • skills/tdd/SKILL.md
   • skills/react-19/SKILL.md
   • skills/typescript/SKILL.md
   • skills/tailwind-4/SKILL.md
   • skills/vitest/SKILL.md
   • skills/pytest/SKILL.md
2. Confirm each file now follows the same top-level shape:
   • Activation Contract
   • Hard Rules
   • Decision Gates
   • Execution Steps
   • Output Contract
   • References
3. Spot-check that skills/pytest/SKILL.md no longer depends on external references in the main skill body
4. Confirm the batch remains limited to generic cross-project skills only

Validation performed:

• Structural RED/GREEN validation for one-line trigger-first descriptions, required section order, and local-only references
• skill-sync intentionally skipped because metadata surfaces did not change

Checklist

Community Checklist

• This feature/issue is listed in here or roadmap.prowler.com
• Is it assigned to me, if not, request it via the issue/feature in here or Prowler Community Slack

• Review if the code is being covered by tests.
• Review if code is being documented following this specification https://github.com/google/styleguide/blob/gh-pages/pyguide.md#38-comments-and-docstrings
• Review if backport is needed.
• Review if is needed to change the Readme.md
• Ensure new entries are added to CHANGELOG.md, if applicable.

SDK/CLI

• Are there new checks included in this PR? No
  • If so, do we need to update permissions for the provider? Please review this carefully.

UI

• All issue/task requirements work as expected on the UI
• Screenshots/Video of the functionality flow (if applicable) - Mobile (X < 640px)
• Screenshots/Video of the functionality flow (if applicable) - Table (640px > X < 1024px)
• Screenshots/Video of the functionality flow (if applicable) - Desktop (X > 1024px)
• Ensure new entries are added to CHANGELOG.md, if applicable.

API

• All issue/task requirements work as expected on the API
• Endpoint response output (if applicable)
• EXPLAIN ANALYZE output for new/modified queries or indexes (if applicable)
• Performance test results (if applicable)
• Any other relevant evidence of the implementation (if applicable)
• Verify if API specs need to be regenerated.
• Check if version updates are required (e.g., specs, Poetry, etc.).
• Ensure new entries are added to CHANGELOG.md, if applicable.

License

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.